Anyhelp on HS physics - plz

Colleges & Universities California Institute of Technology
1

<p>Could anyone help me, well sort of finding the value of v, the axis part is ok…</p>

<p>A binary star consists of 2 dense spherical masses of 10(power of 30) kg and 2 x 10(power of 30) whose centres are 10(power of 7) km apart and which rotate together with a uniform angular velocity w about an axis which intersects the line joining their centres. Assuming that the only forces acting on the stars arise from their mutual gravitational attraction, and that each mass may be taken to act at its centre, show that the axis of rotation passes through the centre of mass of the system and find the value of w.</p>

<p>I really appreciate if u could help a poor disabled (am confined 2 a wheelchair for - 3days remaining) guy liked me. lol…</p>

2

<p>could anyone suggest the value of the ratio w relative to earth’s average w?</p>

3

<p>Hint:</p>

<p>Uniform angular velocity = circle.
When something’s traveling in a circle, the centripetal force is F = ma = ??</p>

<p>… if you can figure out that much, there’s your answer.</p>

4

<p>F=Gm1m2/d^2=m1w^2R1=m2w^2R2
R1+R2=d</p>

<p>You can solve for R1\R2\w. You can also find the center of mass by the formula: x=Sum(mixi)/Sum(mi) or just by looking at it.</p>

<p>These problems always have similar approaches.</p>

<p>I don’t know if it’s right to tell you these …
Good luck, anyway!</p>

5

<p>yeah…one thing that’ll help…Fgrav = Fcentripetal…as Fgrav is the only force acting on the stars, and since the stars are moving in a circular orbit, there must be an Fcentripetal…</p>

<p>…work with that and everything above</p>

6

<p>Yeah, thank you a lot.</p>